If you go to global and click one of the varying circledot options, the list of posts which appears all seem to be posts with one more circledot than the one that you selected.
This may be related to what I've sometimes noticed and will dub the "phantom circledot problem," which is that in my feed I'll see posts with 8 circledots but which say 7 people shared, and if you click to see who shared, you'll only end up with 7 names. Not sure if this is meant (a la vote fuzzing) or accidental